Method of producing battery separator blanks



June l2, 1928.

E. P. FAY

METHOD OF PRODUGING BATTERY SEPARATOR BLANKS Filed July 26. 1927 Patented .lune 12, 1928.

ELI` P. FAY, OF LOS ANGELES, CALIFORNIA.y

METHOD' `0]? PRODUCING BATTERY SEPARA'IOR BLANKS.

Application filed July 26, 1927. Serial No. 208,639.

This invention relates to an improved method of producing battery separator blanks. I have found in practice that battery separators made out of Wood and prepared by the old .method of trinuning to finished size before expanding the fibre by steaming are objectionable because the separators become irregular in size by the subsequent steaming and treating which is necessary to remove impurities before use in batteries. This irregularity in size renders the separators less effective in performing their function. It is the primary object of this invention to overcome this objection in a .simple and effective manner.

In the accompanying drawing forming part of this specification, Fig. 1 is a diagrammatic plan of four units of construction which are adapted to produce my improved product by my improved method;

ig. 2 is a perspective view of one of the battery separator blanks produced by my improved method; Fig. 3 is a perspective vfew of one of the blocks of Wood from which the separator blanks may be sliced, and Fig. 4 is a perspective View of a pack of battery separator blanks Which may be used in the production of my improvement by an alternative method.

In carrying my improved method into practice, logs or slabs of Wood, preferably White cedar after being seasoned and squared are cut into blocks of substantially even lengths corresponding with the lengths of the finished battery separator blanks. This first step of cutting into even lengt-hs performed by the cross cut saw A (see Fig. 1), on which the log 10 is laid and the saw blade 11 moved to cut the log as stated into block-s 12. The block of Wood so cut are then placed in a steamer B and after being thoroughly boiled to fully expand the fibre, they are placed in the trimmer C and their opposite sides trimmed evenly to produce uniformity in the size of the blanks which are ultimately produced. This trimming operation is set forth in my companion application for patentcovering improve-ments in trimming machines, filed simultaneously With this application. From this trimmer the blocks are placed in the slicing machine I) and cut into battery separator blanks 13 of uniform Width and thickness. This slicing machine is fully described in application for patent Serial Number 131,905, filed Aug. 27, 1926, by William J'. Rehrig and assigned to myself. l After slicing' the blocks, the blanks are dried, grooved and then treated with caustic or other chemical or chemicals to free the material from oils, acids and other deleterious substances, to remove impurities. As a resuit of this process of trimming into proper dimensions when fully expanded by steaming or boiling the blanks are adapted 'to again assume these Isame dimensions evenly when ultimately used in a battery. Although it is true that the separator blanks are of uneven width after being dried and grooved due to uneven contracting of the cells during drying, nevertheless these uneven dry blanks when properly treated Will reexpand to their original trimmed Width. This is due to the fact that the Water enters the cells and takes the place of the resins and impurities that have been given off during the treatment. These separators are retained in a moist condition until placed in the battery.

The method may be modified Within the spirit of my invention and the slicing step of the process made to precede the trimming of the edges in which event a pack of slices, in fully expanded condition, due to steaming or boiling and resembling a block suoli as shown in Fig. 4, may be placed in the trimmer and their side edges trimmed to produce blanks of uniform width and in substantially the same expanded condition as they assume when used in a battery.

By trimming when expanded to the exact uniform condition which separators assume when used in a battery, an improved product is produced which has a certain important characteristic which distinguishes it from Wood battery separators not produced by my improved method, namely, uniformity in width Without retrimming This characteristic also permits of manufaetunl ing and selling separators in dry condition, said dry separators not requiring any further trimming after treatment Which has in the past been necessary.

Having described my invention what I cla-im as new and desire to secure by Letters `atent is:

l. The method of producing battery separator blanks, which consists of cutting squared logs of Wood suitable forbattery separator blanks into blocks of desired length, treating said blocks to expand the material thereof, trimming the sides of said expanded blokfs, slicing said' blocks into blanks of uniform. thickness and width While expanded, dryingl said blanks, grooving the dry blanks and finally treating; said blanks while expanded to remove impurities.

2. The method of producing battery separator blanks, which consists of cutting squared logs of wood suitable for battery separator blanksA intoblocks of: desired length, treating said blocks to expand the material thereof, slicing;y said. blocks inta blanks of uniform thickness andl Width While expanded and trimming the side edges 0i the expanded4 material, drying said blanks, grooving the dry blanks and finally treating saidlblanks while; expanded to :we lnove impurities.

In witness whereof I have signed my name to this specification.

ELI P. FA Y2. 

